Project description:Abstract Background Drought stress is one of the major factors limiting wheat production globally. Improving drought tolerance is important for agriculture sustainability. Although various morphological, physiological and biochemical responses associated with drought tolerance have been documented, the molecular mechanisms and regulatory genes that are needed to improve drought tolerance in crops require further investigation. We have used a novel 4-component version (for overexpression) and a 3-component version (for underexpression) of a barley stripe mosaic virus-based (BSMV) system for functional characterization of the C2H2-type zinc finger protein TaZFP1B in wheat. These expression systems avoid the need to produce transgenic plant lines and greatly speed up functional gene characterization. Results We show that overexpression of TaZFP1B stimulates plant growth and up-regulates different oxidative stress-responsive genes under well-watered conditions. Plants that overexpress TaZFP1B are more drought tolerant at critical periods of the plant’s life cycle. Furthermore, RNA-Seq analysis revealed that plants overexpressing TaZFP1B reprogram their transcriptome, resulting in physiological and physical modifications that help wheat to grow and survive under drought stress. In contrast, plants transformed to underexpress TaZFP1B are significantly less tolerant to drought and growth is negatively affected. Conclusions This study clearly shows that the two versions of the BSMV system can be used for fast and efficient functional characterization of genes in crops. The extent of transcriptome reprogramming in plants that overexpress TaZFP1B indicates that the encoded transcription factor is a key regulator of drought tolerance in wheat.
Project description:Bread wheat (Triticum aestivum) is a staple food crucial for global caloric intake and food security. The current climate emergency demands the development of sustainable agricultural practices, particularly in the context of drought-induced yield reductions in bread wheat. Microalgae-based biostimulants have emerged as promising tools to enhance crop tolerance to drought stress while concurrently mitigating atmospheric CO2 accumulation. This study characterizes the transcriptomic responses to the foliar application of the microalgae-based biostimulant LRMTM in drought-stressed and fully irrigated wheat plants unveiling its mode of action. Drought stress at the tillering stage significantly altered gene expression activating key pathways related to phosphate starvation response (PSR), inositol phosphate signaling, and tocopherol biosynthesis. The application of the microalgae-based biostimulant LRMTM in drought-stressed plants further enhanced the expression of drought-responsive genes, particularly those involved in PSR and carbon fixation. Specific responses to LRMTM treatment in drought-stressed plants were also found related to abscisic acid (ABA) signaling activating genes involved in stomata closure, which plays a critical role in drought tolerance. In fully irrigated plants, LRMTM treatment was also beneficial modulating circadian rhythms, shade avoidance and attenuating stress responses. Phenotypic analysis showed that LRMTM-treated plants exhibited enhanced drought tolerance, increased height and spike length even under fully irrigated conditions. These results indicate that the microalgae-based biostimulant LRMTM not only enhances wheat response to drought but also promotes growth and productivity in both stressed and non-stressed conditions which could contribute to the development of sustainable agriculture in the face of the current climate challenges.
Project description:To better undersand the effects of drought stress on wheat developing seeds, the transcription profile of early developing wheat seeds under control and drought stress conditions were comparatively analyzed by using the Affymetrix wheat geneChip. Drought stress is a major yield-limiting factor for wheat. Wheat yields are particularly sensitive to drought stress during reproductive development. Early seed development stage is an important determinant of seed size, one of the yield components. We specifically examined the impact of drought stress imposed during postzygotic early seed development in wheat. We imposed a short-term drought stress on plants with day-old seeds and observed that even a short-duration drought stress significantly reduced the size of developing seeds as well as mature seeds. Drought stress delayed the developmental transition from syncytial to cellularized stage of endosperm. Coincident with reduced seed size and delayed endosperm development, a subset of genes associated with cytoskeleton organization was misregulated in developing seeds under drought-stressed. Several genes linked to hormone pathways were also differentially regulated in response to drought stress in early seeds. Notably, drought stress strongly repressed the expression of wheat storage protein genes such as gliadins, glutenins and avenins as early as 3 days after pollination. Our results provide new insights on how some of the early seed developmental events are impacted by water stress, and the underlying molecular pathways that can possibly impact both grain size and quality in wheat.
Project description:To better understand the regulatory mechanisms of water stress response in wheat, the transcript profiles in roots of two wheat genotypes, namely, drought tolerant 'Luohan No.2' (LH) and drought susceptible 'Chinese Spring' (CS) under water-stress were comparatively analyzed by using the Affymetrix wheat GeneChip®. A total of 3831 transcripts displayed 2-fold or more expression changes, 1593 transcripts were induced compared with 2238 transcripts were repressed, in LH under water-stress; Relatively fewer transcripts were drought responsive in CS, 1404 transcripts were induced and 1493 were repressed. Comparatively, 569 transcripts were commonly induced and 424 transcripts commonly repressed in LH and CS under water-stress. 689 transcripts (757 probe sets) identified from LH and 537 transcripts (575 probe sets) from CS were annotated and classified into 10 functional categories, and 74 transcripts derived from 80 probe sets displayed the change ratios no less than 16 in LH or CS. Several kinds of candidate genes were differentially expressed between the LH and CS, which could be responsible for the difference in drought tolerance of the two genotypes.
Project description:Bread wheat (Triticum aestivum) is a major component of half the global population’s diet, but increasingly frequent droughts threaten its productivity and food security. While massive transcriptional reprogramming under drought in wheat seedlings is well characterised, DNA methylation’s contribution remains poorly understood. Using paired whole-genome bisulphite sequencing (WGBS) and RNA-seq before and after drought stress in wheat landraces, we probed the nuanced role of DNA methylation in the drought response, uncovering antagonistic trends between cytosine contexts and novel mechanisms, with the ROS1a family potentially playing a key demethylation role under drought. Examination of gene methylation profiles revealed that gene body methylation was strongly positively correlated with gene expression but negatively with stress responsiveness, simultaneously identifying that gene body differentially methylated regions (DMRs) targeted stress-associated genes. Many DMR-associated genes maintained consistent transcription under stress, suggesting a stabilising role for DNA methylation. Most DMRs localised to intergenic regions and transposable elements (TEs), with the ancient LTR retrotransposon RLX_famc9 emerging as a critical target of differential methylation under drought. We propose a model in which the RLX_famc9 family, enriched in differential methylation and exhibiting substantial sequence similarity to drought-responsive genes, is involved in the trans-regulation of stress-associated genes under control conditions through the generation of regulatory siRNA precursors, a mechanism suppressed by drought-inducible hypermethylation. Our findings suggest an intricate regulatory role of DNA methylation under drought, with genic DNA methylation promoting high, stable expression, ROS1a glycosylases coordinating targeted demethylation, and methylation-controlled TEs modulating the expression of downstream genes in trans.
Project description:Water deficit stress between the booting and grain filling stages significantly affect grain yield and quality of hard red winter wheat. Several stress tolerant cultivars with different adaptation mechanisms have been released and are widely cultivated on the Southern Great Plains of the US. However, the physiological, molecular, and genetic basis of adaptation to drought stress for these cultivars remains unknown. Use of transcriptome profiling to identify drought responsive genes in hexaploid wheat is a challenging process given the quantitative nature of drought stress, genome complexity, and the intricacy of interaction effects. If the information generated from functional genomics studies is to be used in molecular breeding programs for cultivar development, it is highly desirable to use cultivars better adapted for the region. In the current study we used two well-adapted, drought-tolerant, high-yielding, cultivated varieties, TAM 111 and TAM 112, which appear to have different adaptation mechanisms, to identify drought stress induced transcripts during heading and early dough stages. A set of 24 Affymetrix GeneChip wheat genome arrays (2 cultivars; 2 water treatments; 2 sampling stages; 3 biological replicates) from plants subjected to water deficit stress under controlled glasshouse conditions. Differentially expressed genes were identified using a ANOVA (p<0.01) controlling false discovery rate (FDR, q<0.01) using Benjamini Hochberg approach.
Project description:More than four billion people rely on bread wheat (Triticum aestivum L.) as a major constituent of their diet. However, the changing climate threatens wheat production, with periods of intense drought stress already causing widespread wheat yield losses. Much of the research into the wheat drought response has centred on the response to drought events later in development, during anthesis or grain filling. But as the timing of periods of drought stress become increasingly unpredictable, a more complete understanding of the response to drought during early development is also needed. Here, we utilized the YoGI landrace panel to identify the key genes regulating processes such as, stomatal opening, stomatal closing, stomatal morphogenesis and stress hormone signalling related to drought stress.
Project description:A complex regulatory network is the mechanism of wheat roots responding to drought stress at low and adequate phosphorus levels. The transcription levels of genes encoding silicon transporters, phosphate transporters, sucrose synthesis, etc., are mostly up-regulated in Xindong20. The genes encoding the electron transport chain and the respiratory chain are mostly down-regulated in Xindong23. These results suggest that wheat roots should maintain the structural integrity of the cells and reduce the energy metabolism during the coupled stress of drought and low phosphorus, which will help to improve the drought tolerance of wheat. The objective of the present data was to increase the information about the effect of drought on the transcriptomes of wheat root cultured by two phosphorus levels.
Project description:Background Maintaining global food security in the context of climate changes is an important challenge in the next century. Improving abiotic stress tolerance of major crops, like wheat, can contribute to this goal. Therefore, new genes improving tolerance to abiotic stresses, like drought, are needed to support breeding programs aimed at producing more adapted cultivars. Recently, we screened five wheat Zinc Finger Proteins (TaZFPs) and identified TaZFP13D as a new gene improving water-stress tolerance. However, a more detailed characterization of this gene is required to better evaluate its potential in drought tolerance and to decipher the underlying molecular basis. Results We used the Barley Stripe Mosaic Virus to up- or down-regulate TaZFP13D expression in wheat. Overexpression of TaZFP13D under well-watered conditions enhances growth as indicated by improved biomass. Exposing plants to a severe drought stress revealed that TaZFP13D strongly increases survival rate and stress recovery. In addition, TaZFP13D reduces drought-induced oxidative damages, at least in part by improving key antioxidant enzymes activity. Conversely, down-regulation of TaZFP13D decreases drought tolerance and protection against drought-induced oxidative damages. RNA-seq-based transcriptome analysis showed that many genes regulated by TaZFP13D were previously shown to improve drought tolerance, while many others are related to the photosynthetic electron transfer chain and are proposed to improve photosynthesis efficiency and chloroplast protection against ROS damages. Conclusion This study highlights the important role of TaZFP13D in wheat drought tolerance, contributes to unravel the complex regulation governed by TaZFPs, and provides a useful marker to select more drought tolerant wheat cultivars.
Project description:The central part of Brazil, consisting mostly of the Cerrado Biome, is considered to be the new frontier for increasing Brazilian wheat production. However, rainfed wheat production in that area must cope with drought stress. In order to better understand the drought response, we analyzed the mRNA profiling under drought in roots and leaves of the cultivar MGS1 Aliança (a well-adapted cultivar to the Cerrado). We identified 4,422 candidate genes in roots and leaves.